XMLEXISTS

XMLExists checks whether a given XQuery expression returns a nonempty XQuery sequence. If so, the function returns TRUE; otherwise, it returns FALSE. The argument XQuery_string is a literal string, but it can contain XQuery variables that you bind using the XML_passing_clause.

The expr in the XML_passing_clause is an expression returning an XMLType or an instance of a SQL scalar data type that is used as the context for evaluating the XQuery expression. You can specify only one expr in the PASSING clause without an identifier. The result of evaluating each expr is bound to the corresponding identifier in the XQuery_string. If any expr that is not followed by an AS clause, then the result of evaluating that expression is used as the context item for evaluating the XQuery_string.